Pump



Mar. 13, 1923.

G. C. GARRAWAY PUMP Filed Sept. 15, 1921 INVENTOR BY' 7 ATT NEY of the piston shown in elevation. 2 is a section on line 2-2 in Figure 1, and

Patented Iii/liar. 13, 1923 nnrrnn inane GEORGE c. GAREAWAY, on nu'rnnnronn, NEW JERSEY.

P'UME.

Application filed September 15, 1921. Serial No. 500,747.

The invention is, illustrated, in the accom panyin'g drawing, in which Figure 1 is a section of my improved pump with one end Flgure Figure/.3 is a section of the central part of the pump with the valves shown in position,

which is the reverse of that shown in Figurel.

The pump comprises a cylinder 10 which has suitable inlet ports 11 and outlet ports 12, these being preferably arranged in the heads 13 of the cylinder and also having check valves 14 to control the passage of air or thel-ike through them, the outlet ports being preferably connected by tubes 15 to an outletpipe 16.

A hollow piston 17 slides within the cylinder 10, and the heads 18 of the piston are provided with any of the usual forms of piston rings 19. Within :the piston, and centrally located therein, is a valve casing 20 which is secured against movement by the inlet pipe 21 and the outlet pipe 22, the pipes passing through the ends of the cylinder and of the piston, and since the piston slides on the pipes, suitable stuffing boxes 23 are provided to prevent leakage. To prevent leakage around .the valve casing I place packing rings 24 which provide a tight joint between the outside of the valve casing and the inside of the piston.

The valve casing'is provided with ports which form passages for fluid under pressure, and also includes valves which are actuated primarily by the piston at the limits of its reciprocating movement so as to automatically force the piston first in one direction and then in the opposite direction, said, valves also providing for the opening and exhausting of ports or passages which conduct fluid under pressure to the exhaust pipe alternately from the opposite sides of the i valve casing.

In the form shown the ends and slides in the chamber 27. The

chamber 27 is connected by a port 28 withthe inlet pipe, and by a port 29 with-the exhaust pipe@ The spool valve '30 slidesin the spool valve chamber 31, the chamber 81 being connected with the inlet pipe by; the

tappet valve 24, has the tappets 25 and 26 on its opposite port 32, and with the outlet pipe the;-

port 33 One end ofjthe spool valve chamber 31 is reduced, as at 34, to receive an extension of the spool valve 30, this extension having its end providedwith a reduced head 35. diate head 36 and an end head 37, the tappet valve having end heads 38 and 39 and an intermediate head 40. 1 Thevalve casing has a port 41 which ex- The spool valve has an interme-w tends from one end thereof and has. itsin ner end opening into the spool valve chamher so that the intermediate head 36 will pass across it in its movement, and? alsohas a port 42 on the opposite end of the ,valve head 35 of the spool valve passes across the inner end of this port 42 in the movement of the spool valve. The port 42 has one end entering the chamber 34 and is disposed sothat the head 35 alternately uncovers and covers it in its movement, this port having its other end in the exhaust pipe, and the port 44 has one end opening intolthetappet valve chamber and disposed sothat the intermediate head 40-passes across it, the other end of this port opening into theispool valve chamber 31 beyond the head 37 of the spool valve, this head being provided with a projecting part 45 so that this end of the port 44 cannot be closed.

The operation of the device is as follows:

Assuming that the piston in Figure 1 is moving to the right, fluid under pressure, for instance, steam, passes through the inlet pipe 21, port 28, chamber 27, port 44 and holds the spool valve in the position shown in Figure 1, which causes the head 35 to uncover the port 42, and steam is thus permitted to enter the. chamber 46 in the piston, which forces the piston to the right, compressing air or any other element between the right hand end of the piston and the end of the cylinder and closing the inlet 11 and opening the outlet 12'at this end of the pump.

casing whichis disposed so thatthe reduced.

As the piston completes its movement the inner end of the left hand head 18 of the piston hits the tappet 25 and forces the tappet valve over so that theintermediate head 40 passes to the other side of the end of the port 44, and this port is now connected with the outlet port 29 through the chamber 27, and steam pressure going through the port 32 pushes the spool valve over to the position shown in Figure 3, which permits the exhausting of the chamber 46 through the port 42, chamber 34 and port 43, and steam under pressure passes from'the inlet pipe 21 through-the port 32, chamber 31 and port 41 into the chamber 47' between the valve casmg and the piston head and forces the piston to the left as one looks at the drawing,

and since the tappet 26 is now exposed, the

continued movement of the piston causes the piston head 18 on the right hand end of the piston to hit'the tappet 26 and the parts "resume the position shown in Figure 1, and

these alternate movements of the tappet being continued'by' reason of the movement of the piston, the automatic operation of the piston in the pump is assured.

This pump is well adapted for many uses, and on account of its small size is particularly well adapted for'such uses as the inflation of tires on automobiles driven by steam power and in other situations where a rapid and economical operation of the pump is required.

It will be understood that minor changes in construction can be made without departing from thescope of the invention.

I claim:

1. A pump comprising a cylinder having an inlet and an outlet at each end, a hollow piston in the cylinder, an inlet pipe extending through one end of the cylinder and of e the piston, an outlet pipe extending through theopposite end of the cylinder and of the piston, a valve casing within the piston and having ports in communication with the pipes to supply and exhaust fluid under pressure to and from the inside of the piston, and means actuated by the piston for controlling such admission and exhausting. 2. A pump comprising a cylinder with a reciprocating hollow piston therein, a valve casing within the piston having passages pump tov the inside of the piston, a valve.

casing secured to the inner ends of the pipe, the valve casing having valved passages for controlling the admission and exhaust of fluid under pressure to and from the pipes and the piston, at least one of said valves being disposed so as to be actuated by the piston,

4. A pump comprising a cylinder with a reciprocating hollow piston therein, an inlet pipe extending from one "end of the pump to the inside of the piston, an outlet plpe extending from the opposite end of the pump to the inside of the piston, a valve casing secured to the inner endsof the pipes, the valve casing having passages therein, said passages including two valve chambers, a tappet valve in one chamber and disposed so as to be actuated by the piston, a spool valve in the other chamberand actuated by I fluid. from the inlet pipe and in turn controlling the direction of flow of fluid in the inlet and exhaustpassages.

In testimony that I claim' the foregoing, I have hereto set my hand,ithis 13th day of September, 1921.

GEORGE c. GARRAWAY'. 

